1. Field
The present invention relates to a center management apparatus that manages a center apparatus that performs a process described in a guest program in a virtual machine environment, and in particular, relates to a center management method for facilitating maintenance of the guest program.
2. Description of the Related Art
As personal computers (PCs) have become widely available, protection of important data stored in PCs used by individual employees and maintenance costs of many PCs have caused problems in enterprises. A thin client system attracts attention as a solution to these problems (for example, see Japanese Laid-open Patent Publication No. 2003-158534). A thin client system is a computer system in which, instead of performing an application using a PC, the application is performed by accessing, from a remote terminal via a communication network, a server or a PC that is managed in a center (hereinafter generically referred to as a center apparatus). A thin client system may be implemented in a virtual machine. Specifically, an environment for a user's usage is virtually created in a center apparatus so that it seems to the user who operates a terminal that a real machine provided the environment for the usage is operating. In this case, actually, data for implementing the environment of the user's usage (referred to as a guest program) is managed in a center, and a virtual machine based on the guest program is activated in an appropriate center apparatus in response to a request for usage from the user. In other words, the guest program is loaded, and a process described in the guest program is performed, so that it seems to the user who operates the terminal that a real machine is operating. A plurality of virtual machines may be constructed in a single center apparatus.
Moreover, when a maintenance process such as virus check and update of an operating system (OS) is performed on a guest program, a virtual machine based on the guest program is activated in an appropriate center apparatus, and the virtual machine performs a process described in a maintenance program. If a maintenance process that changes the guest program is performed during user's usage, the change made by the maintenance process and user's usage conflict with each other. Thus, the maintenance process cannot be performed during user's usage. Even in a case where the maintenance process for the guest program is started when it is not used by the user, the user may start usage in the middle of the maintenance process. Thus, it is necessary to refuse user's usage until the maintenance process has been completed.
As a technique for handling a conflict between user's usage and a maintenance process, for example, an automatic maintenance method for a database is provided (see Japanese Laid-open Patent Publication No. H06-243011). The method is provided to automatically determine, on the basis of data indicative of the operation of a database, a time period during which a maintenance process can be performed.
Even when the technique discussed in Japanese Laid-open Patent Publication No. H06-243011 is used, user's usage needs to be refused during the maintenance process.